I agree a world record cant happen in your gym, at anytime. It has to be during competition. Everyone has those days where they are in the zone. You have to bring that to a competition.
So then why not Hafthor bring it to a competition then pull that much weight then be a done deal. I think he can pull that 501kg again at a competition. Eddie would need to get back into the training game if he wants to take a bite of that apple.